In semiconductor devices, or circuit board packages, atoms (specially Cu) forming a wiring are ionized during an operation, and these ionized atoms move into an insulating film by electric field, or move cross an interface with another material around the wiring, which cause a problem in significantly reducing service life of the wiring.
As for a method for preventing the movement of the atoms, there are a method for covering a surface of a wiring with a metal having higher resistance than that of the wiring material, and a method for forming a barrier layer on the wiring. Examples of the method for forming a barrier layer on the wiring include a method in which a barrier layer is formed on an insulating film, and a wiring is formed on the barrier layer, and a method in which a barrier layer is formed on a surface of a wiring after forming the wiring (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2003-505882). In accordance with the latter method, a barrier layer is often formed by electroless plating. If any conductive impurity is present on an insulating film other than on the wiring, the plating grows abnormally using the impurity as a nucleus, which causes failures such as short circuit, and reduction in reliability.
To solve this problem, conductive impurities on an insulating film are conventionally removed by washing using strong acid or strong base before plating.
This method, however, has problems that a wiring and an insulating film are damaged, or a production process becomes complicated.
In a production method of a semiconductor device, as a method for forming a fine pattern, there is proposed a method contains a step for applying a water-soluble composition so as to over a surface of a resist pattern to thereby swell the resist pattern, and a step for pattering an underlying layer by performing dry etching using the swollen resist pattern as a mask (see, for example, Japanese Patent (JP-B) No. 3633595).
In this proposed method, however, the aforementioned problems that failures such as short circuit and reduction in reliability occur due to the presence of conductive impurities on an insulating film other than a wiring are not discussed.
Accordingly, it is currently desired to provide a surface coating method capable of capable of preventing abnormal growth on an insulating film due to conductive impurities without damaging wirings and the insulating film, and to provide a semiconductor device and a circuit board package produced using the method.